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          <th colspan="3" align="center">DbSequence::open()</th>
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                The DbSequence Handle 
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            <h2 class="title" style="clear: both"><a id="seqopen"></a>DbSequence::open()</h2>
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      <pre class="programlisting">#include &lt;db_cxx.h&gt;

int
DbSequence::open(DbTxn *txnid, Dbt *key, u_int32_t flags); </pre>
      <p>
         The <code class="methodname">DbSequence::open()</code> method opens the sequence represented by the
         <span class="bold"><strong>key</strong></span>. The key must be compatible with
         the underlying database specified in the corresponding call to 
         <a class="xref" href="seqcreate.html" title="DbSequence">DbSequence</a>.
    </p>
      <p>
         The <code class="methodname">DbSequence::open()</code> <span>
            
            <span>
                method either returns a non-zero error value or throws an
                exception that encapsulates a non-zero error value on
                failure, and returns 0 on success.
            </span>
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      <div class="sect2" lang="en" xml:lang="en">
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              <h3 class="title"><a id="idp10137000"></a>Parameters</h3>
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                <h4 class="title"><a id="idp10136352"></a>key</h4>
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          <p>
                          The <span class="bold"><strong>key</strong></span> specifies which record in the
                          database stores the persistent sequence data.
                     </p>
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        <div class="sect3" lang="en" xml:lang="en">
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                <h4 class="title"><a id="idp10124960"></a>flags</h4>
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                          The <span class="bold"><strong>flags</strong></span> parameter must be set to 0
                          or by bitwise inclusively <span class="bold"><strong>OR</strong></span>'ing
                          together one or more of the following values:
                     </p>
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                  <code class="literal">DB_CREATE</code>
            </p>
                <p>
                 Create the sequence.  If the sequence does not already exist and the
                 <code class="literal">DB_CREATE</code> flag is not specified, the 
                 <code class="methodname">DbSequence::open()</code> method will fail.
            </p>
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              <li>
                <p>
                 <code class="literal">DB_EXCL</code>
            </p>
                <p>
                 Return an error if the sequence already exists.  This  flag is only
                 meaningful when specified with the <code class="literal">DB_CREATE</code>  flag.
            </p>
              </li>
              <li>
                <p><a id="seqopen_DB_THREAD"></a>
                  <code class="literal">DB_THREAD</code>
            </p>
                <p>
                 Cause the <a class="link" href="seq.html" title="Chapter 12.  The DbSequence Handle">DbSequence</a> 
                 handle returned by <code class="methodname">DbSequence::open()</code> to be
                 <span class="emphasis"><em>free-threaded</em></span>; that is, usable by multiple
                 threads within a single address space.  Note that if multiple threads
                 create multiple sequences using the same database handle that handle
                 must have been opened specifying this flag.
            </p>
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        <div class="sect3" lang="en" xml:lang="en">
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                <h4 class="title"><a id="idp10141496"></a>txnid</h4>
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          <p>
                          If the operation is part of an application-specified transaction, the
                          <span class="bold"><strong>txnid</strong></span> parameter is a transaction
                          handle returned from <a class="xref" href="txnbegin.html" title="DbEnv::txn_begin()">DbEnv::txn_begin()</a>; if the
                          operation is part of a Berkeley DB Concurrent Data Store group, the
                          <span class="bold"><strong>txnid</strong></span> parameter is a handle returned
                          from <a class="xref" href="envcdsgroup_begin.html" title="DbEnv::cdsgroup_begin()">DbEnv::cdsgroup_begin()</a>;
                          otherwise NULL. If no transaction handle is specified, but the
                          operation occurs in a transactional database, the operation will be
                          implicitly transaction protected. Transactionally protected operations
                          on a <a class="link" href="seq.html" title="Chapter 12.  The DbSequence Handle">DbSequence</a>  handle
                          require the <a class="link" href="seq.html" title="Chapter 12.  The DbSequence Handle">DbSequence</a> 
                          handle itself be transactionally protected during its open if the open
                          creates the sequence.
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      <div class="sect2" lang="en" xml:lang="en">
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              <h3 class="title"><a id="idp10133224"></a>Class</h3>
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        <p>
                 <a class="link" href="seq.html" title="Chapter 12.  The DbSequence Handle">DbSequence</a>  
            </p>
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      <div class="sect2" lang="en" xml:lang="en">
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              <h3 class="title"><a id="idp10147552"></a>See Also</h3>
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        <p>
                     <a class="xref" href="seq.html#seqlist" title="Sequences and Related Methods">Sequences and Related Methods</a> 
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